粉末原料粒径对WC-17Co涂层性能的影响

Effect of feedstock size on the properties of WC-17Co coatings

摘要:

本文利用超音速火焰喷涂技术喷涂四种不同粒径的WC-17Co粉末,评价粉末粒径对涂层机械性能和抗磨粒磨损性能的影响。结果表明,粉末的粒径越小,在超音速焰流作用下获得的速度和温度越高,形成的涂层越致密,颗粒间的粘接强度越高,同时涂层的显微硬度也越高。WC-17Co粉末的粒径越小,获得涂层的孔隙直径越小,颗粒间的粘接缺陷越少,因此涂层的抗磨粒磨损性能越好。但是当WC-17Co粉末的粒径过于微小时,涂层的断裂韧性将受到影响。在本文研究的四种粒径分布的WC-17Co粉末中,中间粒径且分布范围集中的粉末制得的涂层兼具良好的机械性能和抗磨粒磨损性能。

关键词:原料粒径; 超音速火焰喷涂; WC-17Co; 机械性能; 磨粒磨损

Abstract:

High velocity oxy-fuel (HVOF) spray technique has been utilized to fabricate WC-17Co cermet coatings. To achieve a high performance of mechanical properties and abrasive wear resistance, four types of WC-17Co powders with different feedstock particle size were investigated. The results show that the feedstock powder with finer particle size had higher velocity and temperature during spraying process, resulting in a denser coating and a stronger splat-splat bonding. It was found that the micro-hardness of WC-17Co coating increased with the decreasing of feedstock size. The coating deposited by finer feedstock powder had superior abrasive wear resistance, attributing to the smaller porosity and boundary flaws on coating. However, coating fracture toughness could be affected by feedstock size if it is too small. Among all those investigated, the one with medium particle size and narrow size distribution exhibited both excellent mechanical properties and wear resistance.

Key words:feedstock size; HVOF; WC-17Co; mechanical properties; abrasive wear